palmer



M. W. PALMER CONTROL MECHANISM Filed Jan. 4, 1927 March 13, 1928.

2 Sheets-Sheet 1 INVEN TOR. WM.

BY M ATTORNEYS.

March 13, 1928.

M. W. PALMER coNTRoL MECHANISM Filed Jan. 4, 1927Y 2 Sheeis-Sheet 2 I NV EN TOR.

A TTORNEYS.

Patented Mar. 13, 1928.

UNITED STATES MERVYN w. immuun, or NEW YORK, N. Y.,

AASSIGNOB. TO PARAQMOUNT FAMOUS LASKY CORPORATION, OF NEW YORK,'N. Y., ACORPORATION OF NEW YORK.

CONTROL MECHANISM.

. Application iled- January 4, 1927. Sferial No. 159,010.

My invention broadly relates to automatic electric control devices andhas for one of its objects the provision of automatically operatingcontrolling mechanism whereby the voltage in a line may be maintainedwithin very close limits, or, stating it 1n another way, automaticallyoperating controlling mechanism governed bythe resistance in the circuitbeing controlled and arranged so as to maintain theresistance in theline within certain predetermined limits. While my improved apparatus iscapable of numerous applications such as electric furnace installations,automatic electric elevator operation, search-lights, arc-lights :for

medical uses, projection machines and spotlights, it will, for the sakeof clarity, be described with specific reference to spot-lights. .In aspot-light, as is well known, current is passed between spacedelectrodes, and in f the carbon arc, that is to say arcs employingcarbon electrodes, the carbon itself is the source of light, while inthe high intensity arc the carbon acts as a holder for the real sourceof light, which is a small body of luminous gas. In both types' of arc,however, it is necessary to effect a'periodic adjustment of theelectrodes in order that the arc voltage may be maintained within pre-3o determined limits, or, stating it another way, the resistance acrossthe electrodes must be maintained substantially constant,`

for best` results.

With the spot-lights employed in moving picture studio and theatre work,vit is customary to adjust/the electrodes b hand, the adjustment beingmade at the Wi of an foperator whose judgment must be relied upon. Instudio work where a great many 40 spot-lights may be in use at the onetime, it is customary to employ one operator for each machine, which ofcourse imposes a heavy operating expense uponeach machine, and inasmuchas the human element in such cases must be relied upon, results are notalways what may be desired. j

To avoid the annoyance and expense incident to the old method as justoutlined of effecting the proper adjustment of the arc, I provide meansapplicable tofcarbon arcs as well as high intensity-arcs wholly auto`matic in its operation and controlled by the arc voltage whereby avariation in this voltage beyond certain prescribed limits will effeet arestoration of the electrodes to a predetermined relation andlre-establishment of the proper'arc voltage.

More specifically 1n invention contemplates the provision oi areversible electric motor mechanically and electrically connected' tothe electrodes to be "controlled, whereby upon an increase or -decreasein the arc voltage the motor will be energized to effect rotation of thesame in the proper direction to in turn move the electrodes in theproper direction to restore or re-establish normal operating conditions.

In the accompanying drawing illustrating the application of ymyinvention to a spotlight of the carbon arc`type, as well as highintensity arcs, X

Fig. 1 is a wiring diagram of my invention;

Fig. 2 is a part sectional elevational view of the apparatus which maybe employed in the commercial use of the invention;

Fig. 3 is asection through Fig. 2 taken on the line 3 3 thereof;

Fig. 4 is a section through Fig. 2 taken on the line 414; v

Fig. 5 shows my invention high intensity arc;

F F ig. 6 is a section on the line 6-,6 of

Fig. 7 is a wiring diagram modified as to the diagram of Fig. 1; and

F ig.,8 is a Wiring diagram of a still further modification.

Referring to the drawings in detail and first of all to Figs. 2, 3 and4, l desi ates a lamphouse which may be of usua con struction. Mountedwithin the lamphousc on suitable guides 2 is a carriage 3 carrying theelectrodes 4 and 5. The electrode 4 is carried in a holder and theelectrode 5 in a holder 7,1 the holders 6 and 7 in turn beapplied to aing threaded upon a lrod 8 mounted for rotation but held againstIlongitudinal movev.ment in the'carriage. The threaded ortion 9 oi therod 8 which receives the ho der 6 is threadedoppositelyto the portion 10carrying the holder 7, so that rotation of the rod 8 will effectmovement of the holders Cin opposed directions.

Mounted on the under side of the lamphouse is a platform, shelf or othersintlilo ' holding t able support 11 'fon a reversible electric motor12, the armature shaft of whlch isA designated 13.. i

The armature shaft 13 carries a worm 14 meshing with a worm wheel 15carried on a stub shaft 16. The shaft 16 1s connected lby a universaljoint 17 to a stub shaft or rod 18 having telescopic connection to a rod19 connected by a universal joint 20 to the threaded rod 8 carrying theelectrodes.

The worm Wheel 15 is free onv the shaft r16, but a driving connectiornvis normally maintained between these two members by a clutch. Thisclutchisfillustrated in Fig. 4, and `from this Vfigure it will be seenthat the lower side of the worm wheel 15 is'pro- The jointed connectionsabove described .and the clutch mechanism just referred to provide .a`drive from the motor 12, to the rod 8, and rotation of this rod will,it is obvious, adjust the electrodes 4 and 5 relatively and in adirection depending uponthe direction of rotation of the motor.

In operation of the spot-light it is desirable to adjust the electrodeslongitudinalv ly of the lamphouse, that is, to vary. thev distancebetween the` electrods and the lens 26. This adjustment is eiected bysliding the carriage 3 along the guides 2, by means j of a rod 27provided for that'purpose; this l adjustment eingveffected withoutdisturbthe drive between the motor 12 and4 8,' due tothe universaljoints above' described, while the telescopic connection be tween herods 18 and1-9 permits of this adjustment without varying the positionof the arc vertically. y 'f n j Referring to the wiring diagram bt Fig.1, it will be seen that the armature 28 of the motor 12 is connectedacross two branchl circuits designated 29 and '30, the circuit 29 beingprovided with fixed resistance 31 while the circuit 30 is provided withvariable resistance 32. The electrodes 4 and 5 of the -arc are in thebranch circuit 29.

The field of the motor is designated 33 'and as illustrated .isconnected across the velectrodes 4 and 5.

The `operation vof my improved control `mechanism so Ifar as itselectrical features areconcerned and so far as itsautomatic operatlon 1sconcernedjis as follows, assuming that the electrodes 4 and 5 are incontact with eachother and that current is flowing through the branchcircuits 29 and 30. Owing to. the arrangement of the resistances 3l and32, there Will be a diiierence in potential across the terminals of themotor 12 to cause the armature 28 thereof to be energized and hence the`motor to be rotated. The rotating of this armature 28 through 4themechanism described in connection with Figs.,2, 3 and 4 will cause therod 8 to rotate in the proper direction to effect a separation of theelectrodes 4 and 5. When these electrodes have separated a predetermineddistance, the increase in resistance, due to the separation' of theelectrodes 4 and 5, will establish a balance between the branch circuits29 and 30. In other words, there will be no dii'erence in potential atthe terminals of the motor 12 with the result that the motor armature 28will come to rest. As soon as thekelectrodes 4 and 5, or rather thepositive electrode 4, has burned away or disintegrated due to thearcwacross these electrodes suiciently to, so to speak, upset thebalance between the branch circuits 29 and 30, a difference in potentialacross the terminals of the motor 12 will again occur, with the resultthat the arma ture, will be rotated, but this time in the oppositedirection, so as to move the electrodes 4, and 5 toward each other untila balance has been reached again. Consequently, it will-rbe seen that nohand manipulation of the electrodes 4 and `5 is necessary in order tomaintainthevoltage across the electrodes 4 and 5 within predeterminedlimits, with the result that the spotlight will be operated at asubstantially constant voltage.

It will .be understood that-the variable resistance 32 isonly necessaryfor the initial setting of the device, no manipulation of thisresistance being necessary aiter the devlce has once been adjusted, theentire operation of my improved apparatus being automatic.

AIt will beL understood also that if the switch (not shown) controllingthe supplying of power to the electrodes 4 and 5 be opened when theelectrodes are out of contact, al closing of this switch will causecurrent to iiow through the motor 12 in a directionto cause the motor tomove the electrodesv 41 and 5 toward each other. Inasmuch as under theseconditions the arc has not `been struck, it will be obvious that the'motor will continue to so rotate until the electrodes engage eachotheror make contact. When the electrodes contact, themotor vwill reverse indirection, separating th'e electrodes 4'and 5, to strike an arc and willcontinue to rotate in a direction to separate the electrodes until thelatter have beenflseparated the correct distance asdetermined by theinitial setting of the the medium of an electric motor.

machine. Thereafter conditions, so far as operation is concerned, are ashas been described above.

As I have mentioned above, a spot-light has been illustrated anddescribed in detail for illustrative purposes only, inasmuch as myinvention has many applications, some.

of which have been enumerated above. For example, I have mentioned lanelectric furnace as one possible application of my invention, and itWill be obvious to those skilled in this art that in such a case myinvention may be employed to control the resistance and hence thevoltage of the electric circuit of the furnace by inserting in thiscircuit a pair of contacts in which the contact pressure may becontrolled by the motor 12. In other Words, in such a Case it is merelynecessary to substitute such contacts for the electrodes 4 and 5 shownin Fig. 1, the resistance of the circuit instead of varying with thechange in distance between the electrodes 4 and 5, varying with or beingvaried by the pressure of the 'two contacts upon each other.

As above pointed out, my invention is adapted for application to highintensity arcs, and such an application has been illus trated in Figs. 5and 6.

Referring to these two figures of the drawing, 34 and 35 designate,respectively, the positive and negative electrodes of a high intensityarc. The positive electrode 34 is rotated continuously as is customarythrough In the present case, this motor is designated 36 and correspondsto the motor 12 of the embodiment of my invention already described.Also, as is customary, the positive electrode 34 is fed forward, that isto say, in a direction toward the negative electrode 35. The negativeelectrode 35, as distinguished from the positive electrode, isstationary so far as rotation is concerned but is adapted to be adjustedrelatively to the positive electrode 34 by the electric motor 36, aswill be described presently in detail. In other words, as applied tohigh intensity arcs, my invention provides means for maintaining theproper arc voltage at all times as in the case of the carbon arc alreadydescribed.

The positive electrode-34 is mounted on a suitable stand 37 to whichV issecured a bracket or other support 38 carrying the electric motor 36.The negative electrode is mounted in a suitable head 39 supported by anarm 40 carried by the member 37. This part of the apparatus isconventional and will not be described in any great detail for thisreason.

The armature shaft of the motor 36 is designated 41 and is provided witha VWO1-m42 shown clearly in Fig. 6, this Worm meshing with a Worm Wheel43, the latter being mounted on a sleeve 44 which surrounds a ingclutched under ordinary conditions to the worm wheel 43 by teeth 46. Theshaft 45 carries a gear 47 rigidly secured to the shaft and meshing witha gear 48 carried on a short shaft 49 shown in Fig. 6. The upper end ofthis shaft is provided with a bevelled gear 50 meshing with a bevelledgear 51 which in turn meshes with a bevelled gear 52 carried at thelower end of a flexible or jointed shaft 53. This shaft is provided witha universal joint 54 and has a telescopic connection with a shaft 55which in turn is provided with a universal joint 56 and is connected bythis universal joint to a shaft 57 provided With worms 58 and 59, theseworms meshing with Worin gears 6() and 6l, respectively, actuation ofthese worm gears effecting movement of the negative electrode 45longitudinally. We have, therefore, a driving connection from the motor36, that is to say, from the armature shaft 41, to the negativeelectrode 35 whereby rotation of the motor Will eect adjustment of theelectrode. The drive for the positive electrode .34 which, as above(noted, is constantly rotated and fed forward intermittently, comprisesa gear v62 on the upper end of the shaft 45 meshing with bevelled gearon the end ofla drive shaft 64. The opposite end of this drive shaft isprovided with a gear 65 meshing with a bevelled gear 66, the latterdriving a bevelled Gear 67 on the lower end of a shaft 68. This shaft isconnected by a universal joint 69 to a shaft 70, the latter beingconnected by a universal joint 71 to a shaft 72 on the upper end ofwhich is a bevelled gear 73 meshing With a gear 74 connected to thepositive electrode 34 so that rotation of the gear 74 through the geartrain just described by means of the motor 36 Will cause the positiveelectrode 34 to be rotated.' The feed for the electrode 34 is theconventional form and hence will not be described in detail.

The operation of this device is similar to that described in connectionwith the carbon arc illustrated in Fig. 2, the Wiring diagram for themotor 36 being arranged the same as shown inl Fig. 1. In other words,assuming that the switch (not shown) supplying current tothe motor 36 isopened vertically extending shaft45, the sleeve bewhen the electrodes 34and 35 are in the position shown in Fig. 5, closure of this switch willeffect rotation of the motor in a direction to feed the electrodes,particularly the electrode 35, in a direction to bring Ythese twoelectrodes in contact, whereupon,

due to the drop in resistance on account of the contact of the twoelectrodes, the motor will be reversed automatically, the arc willtrodes independently of the motor 36, the` sleeve 44 is pushed upwardlyagainst the'` action ofthe spring 75 so as to disengage the teeth 46from the face of the worm gear' 43.

i This sleeve is keyed or otherwise rigidly secured to lthe shaft 45 andthe shaft may be rotated so as to cause the electrodes to be adjusted.y, A

The wiring.l diagram of Fig. 7 is a modification of the diagram ofFig. 1. Referring to this iigu're of the drawing, the motor 12, theposition of which corresponds to the motor 12of Fig. l, is analternating current 'motor and has its rotor This motor is provided withtwo field windings 7 6 and 77 of diiferent resistances, each iield whenenergized alone producing rotation of the motor in a differentdirection. It will be obvious from an inspection of this diagram thatone or the other of these field windings will be energized when'` anunbalanced condition exists in the circuit. due to improper spacing ofthe electrodes' 4 and 5, and depending upon which field is energized,the motor will be caused to rotate in a corresponding direction, therebyactuating the electrodes 4 and 5 in a vdirection to restore balancedconditions again.

`While the two specific embodiments of my i invention as above describedare suitable for 35. o

certain lclasses of arcs, that is to say, arc lights used forcertainclasses of work. it may be desirable or necessary in some instances touse a larger motor than I have found necessary to use lin the formsillustrated. In such event I propose to employ two motors, one of whichmay be avery powerful motor, relativelyspeaking, and adapted to actuatethe necessary mechanism for effecting the desired electrical conditions.The other motor in this embodiment of my invention may be termed a pilotor control motor, and las it will have practically no work to do exceptthe mere opening and closing of a switch, this pilot or control motormay be of very low capacity, the throwing of the switch by the pilotmotor controlling the circuit of the heavy motor to cause the same tooperate. Inasmuch as the particular switch mechanism and othermechanicalfeatures of this embodiment ofv my invention are of minor importance. Ihave deemed it sutlicient to merely illustrate this feature-of myinvention by way of a diagram, which is the diagram of Fig..8.

Referring to the wiring diagram of Fig. 8, it will be seen that theelectric motor 12, lwhich is provided with twofield windings 7 6 and 77,respectively, is vmechanically connected to a reversing switch 78, thisreversshort-circuited.. v

ing switch controlling the circuit if) a reversible electric motor 79.This motor,

as above pointed out, may be of any neces-Y sary size but isintended'for heavy duty, and it is to be understood will Vbemechanically connected to the device or devices to be controlled, suchas the electrodes 4 and 5, which have been illustrated in this diagrammerely for clarity of description and illustration. The reversing switch78 is adapted to make contact with either contact 80 or 81,'as the casemay be, depending upon conditions across the electrodes or otherdevicesv being controlled. In short, this diagram is intended toillustrate an application of my invention to an insta-llation whereinthe devices 4 and 5, which are to be controlled, are adapted to beactuated bythe reversible motor 79, and as above pointed out, inasmuchas the devices represented by the electrodes 4 and 5 might be of such anature as to require a heavy-duty motor for their actuation,'I haveprovided the heavy-duty motor 79, which is controlled by the relativelylight-duty motor 12. The only work to be performed by the motor 12, as-will be apparent, is actuation of the reversing switch 78. Here, then,I have provided an apparatus wherein lthe direction of rotation of themotor 12 is controlled by the resistance across the members 4 and 5, the

direction of rotation of the pilot or control have provided means formaintainingl the voltage in a line within4 close limits, and` while myinvention is capable of many applications, I have illustrated and'described the samev in connection with a carbon arc spot-light and inconnection with a high intensity arc. It will be seen also thatI haveprovide several embodiments of my invention, so far as theelectricalside thereof is concerned, thel diagram of- Fig. 1 showing al motor withbut one field winding but with the armature winding so arranged that thedirection of rotation of the motor is selected by the resistance acrossthe electrodes 4 and 5. In other words, speaking now of a carbon arcspot-lighthwhen the electrodes are burned awayso that the resistanceacross the electrodes is increased to a point where there is a voltagedrop across the electrodes belill) lll) trodes to strike vthe arc andcontinuing this separation of the electrodes until the voltage acrossthe'same is brought within the predetermined limit.

It will be seen also that in Fig. 7 I have varied this arrangement, inthat the motor is provided with two field windings, the excita# tion ofone field causing the motor to rotate in one direction, while theexcitation of the other field causes the motor to rotate in the oppostedirection, the excitation of these fields being selected by theresistances across the electrodes 4 and 5. In other words. this fembodiment of the invention will operate to maintain the voltage acrossthe electrodes 4 :md5 within the predetermined limits, as in the case ofthe diagram of Fig. 1.

It will be seen also that in Fig. 8 I am able to obtain the same resultselectrically and mechanically, and while in this figure I have modifiedthe wiring diagram of Fig. 7, in that I have added the motor 79 thereto(the motor 12 merely controlling the circuit to this motor), it is to beunderstood that the' motor 79 could be added to the diagram of v Fig. 1,if desired. n

The armature and field connections in theY diagram of Fig. 1 obviouslymay be interchanged, if desired.

It will be obvious that many changes may be made lin the constructionillustrated in the accompanying drawing as above described, wlthouteparting from the spirit of the invention, and accordingl my inventionis not to be limited to t e precise form here shown and described.

What I claim is:

1. In combination, a pair of co-operating electrodes, two branchcircuits, said electrodes being in series with one of said circuits, areversible electric motor having its armature connected across saidbranch circuits, a field for said motor connected across saidelectrodes, and means for mechanically connecting said electrodes tosaid motor, whereby a variation in the voltage of the current flowing inthe circuit containing the electrodes will effect rotation of the motorlarmature to actuate the electrodes and reelectrodes inserted in serieswith one 0 saidv branch circuits, an electric motor mechanicallyconnected to said electrodes for effecting relative adjustment thereof,said motor comprising an armature connected across said branch circuitsand' a field connected across said electrodes, whereby the voltageacross said electrodes will be maintained within predetermined limits.

3. In combination, two branch circuits, an arc light comprising a pairof electrodes inserted in one of said circuits, an electric motorcomprising an armature ymechanically connected to said electrodes andadjustably connected across said branch circuits for determining theoperating position of the electrodes, and a field for said motorconnected across said electrodes.

4. In combination, a pair of branch circuits, an arc light comprisingtwo electrodes inserted in series with onevof said circuits, an electricmotor mechanically connected to said electrodes for adjust-ing the sameautomatically the armature of said motor being adj ustablyconnectedacross said branch circuits for determinin the o erating position of theelectrodes, an the eld for said motor being connected across saidelectrodes.

This specification signed this 3rd day of January, 1927.

MERVYN W. PALMER.

